The present disclosure relates to a method of setting web tensioning in a processing machine, to a processing machine, to a corresponding computer program and to a corresponding computer program product.
Although reference will be made hereinbelow predominantly to printing machines, the disclosure, rather than being limited to this field, is directed to all types of processing machine in which a material web is processed. However, the disclosure can be used in particular in printing machines, e.g. newspaper-printing machines, commercial printing machines, gravure printing machines, inline flexographic printing machines, packaging printing machines or security printing machines, and in processing machines, e.g. bag machines, envelope machines or packaging machines. The material web may be formed from paper, fabric, cardboard, plastics material, metal, rubber, film or sheet material, etc.
In processing machines, in particular printing machines, a material web is moved along driven axes (web-transporting axes) e.g. pulling rollers or advancement rollers, and non-driven axes, e.g. deflecting, directing, drying or cooling rollers. The material web is simultaneously processed, for example printed, punched, cut, folded, etc., by means of usually likewise driven processing axes.
The tensioning of the material web is influenced, for example, via so-called clamping locations, by means of which the material web is clamped in with a friction fit, form fit or force fit. These clamping locations are usually driven transporting or processing units. In the case of a gravure printing machine, a clamping location is customarily formed by a printing unit in which there is a friction fit between the driven impression cylinder, the pressing roller and the material web. The material web is subdivided into web-tensioning portions, wherein a web-tensioning portion is bounded by two clamping locations. Further driven and/or non-driven axes may be arranged within a web-tensioning portion. It is often the case that the entire material web is subdivided into a plurality of web-tensioning portions, in some cases also one with different desired web-tensioning values. For the purpose of maintaining the desired values, use is usually made of web-tensioning regulation.
DE 103 35 885 A1 discloses combined register and web-tensioning regulation. An upstream strategy for the web-tensioning regulation is proposed for the purpose of isolating the register and web-tensioning setting operation. In this case, however, the web-tensioning of the downstream web-tensioning portions is not isolated from the setting operations.
Likewise known downstream strategies, which would make it possible for downstream web-tensioning portions to be isolated, require the activation of the downstream clamping location of the web-tensioning portion. However, if this clamping location cannot be set, it is not possible for isolated web-tensioning setting or regulation to take place.
It is therefore an object of the disclosure to specify an improved method of setting web-tensioning which also allows for clamping locations which cannot be set.
This object is achieved by a method of setting web-tensioning, by a processing machine, by a computer program and by a computer program product, having the features of the independent patent claims. Advantageous developments form the subject matter of the dependent claims and of the following description.